.260 or 6.5 Creed....Vote AR 10 build

Squibbler

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Minuteman
Apr 6, 2014
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Alrighty boys, I'm tired of losing sleep on this one. So, I'm leaving it to the democratic process. Please vote for your favorite in an AR 10. You're welcome to leave your reasoning for your vote, if no reason, then just vote. Up for nomination is .260 and 6.5 Creedmoor. Please only one vote per member. I'll tally the votes down the road and call the race. Will build in the winning cartridge.
 
Yes I'm a handloader. But may buy factory due to time. Trying to forget all the little details in this vote. So pick your favorite and vote. Must only have one vote on your post in order to count.
 
I vote 6.5CM because of mag length and factory ammo. I have a 260Rem bolt gun and I handload so take that for what it's worth. Building a second upper for my Aero M5 12.5" 308Win SBR.
 
You didn't say what you where using it for, so I say 338 Federal.

Appreciate the vote. Everyone is welcome to leave their personal favorite for AR10 but in order to count on this one I'm looking for your favorite between the Creed and .260. As far as intended use, I'm staying vague for a reason, so you are not going to like my response----everything?
 
.260, because of the slight (-ly larger) case volume advantage for starters.

No such thing as a problem finding .260 factory ammo choices anymore, not for a long time now. the 120/130gr choice could be a good choice. Federal .260 Remington Fusion 120gr uses a protected point Spitzer Boattail that should do well in a semi's magazine.

Also, to help out those C/M shooters with their brass supply issues.

You shouldn't be having any brass supply issues with the .260, because if the .260 brass goes to ground, all you need to do is get .243 brass or 7mm-08 brass and simply run it through the F/L die with the sizer ball. Voila!; instant .260 brass.

Here's another trick.

The C/M has a slight case length (shorter) advantage which should allow seating long bullets a bit more easily and still feed in the mags.

But Sierra still carries the 140SMK that we were using way back in 2001 before the 142SMK came out, and that bullet is visibly shorter than the 142, and should help with mag length feeding vs case capacity vs BC issues.

Varget was the original goto powder for the .260, and should be a good burn rate for a semi. It worked at charge levels of 32-36gr(+?), which leaves a good amount of space in the case, so charge compression need not be a serious concern either; and it also leaves more H-4350 on the shelves for the C/M shooters.

Now all of these things will also work with the 6.5CM, but what will you use for brass if the real deal gets sparse? ...And do you really want to be running high priced brass through a gas gun? I make my .260 from HDY 7mm-08 at a nicely competitive cost. ...And there's also Starline.

...And then there's the question of whether all that nice 6.5CM factory ammo is really suited so well to the gas gun. It's still mostly a bolt gunner's world for the 6.5CM, and I think it's a good question whether the factory stuff will be so ideal for the gas gun.

Flip a coin, throw a dart; I'll still suggest the .260 Rem.

Greg
 
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260, you’ll have something way more unique and not be shunned by 1/3 of the shooting community only to be the 2/3 newest fanboy with the creed.
Ballistics are superior and I’d think extraction and feeding would be superior with the 260 as well.
 
The reason the Creedmoor was created and the reason it is so popular is because it fixes all the shortcomings of the 260 rem when a magazine that limits the cartridge over all length is to be used. It also seems the shorter and fatter the cartridge the more inherently accurate it tends to be. This is a no brainer for me Creedmoor all the way. Now if we are talking about a rifle with no magazine oal restriction and the person is a hand loader only then the 260 may have its place.
 
The reason the Creedmoor was created and the reason it is so popular is because it fixes all the shortcomings of the 260 rem when a magazine that limits the cartridge over all length is to be used. It also seems the shorter and fatter the cartridge the more inherently accurate it tends to be. This is a no-brainer for me Creedmoor all the way. Now if we are talking about a rifle with no magazine OAL restriction and the person is a hand loader only then the 260 may have its place.

I honestly wouldn't know how accurate this information is.

What I do know is that Hornady invested deep into developing and marketing the 6.5 Creedmore, in conjunction with Ruger's intro of the RPR.
While the two cartridges are literally one right after the other in Hornady's newest 10 Edition Handloading Manual, that manual goes out of its way to demonstrate the Creedmore as a superior round.

Which it is not.

First, Hornady orders the two cartridges 260 first, 6.5CM second, giving the false impression that the 260 has the smaller case capacity. It has the larger capacity.

Next, it shows the 6.5CM having superior velocities with the same bullet, but for the comparison, the powders chosen for the 260 are not the ideal ones that are chosen for the so-similar 6.5CM. H-4350 doesn't even appear in the 260 section and that's just flatly ludicrous.

The rifles used show the .260 in a Rem 700, and the 6.5CM in a Rem 700/Custom. Experienced shooters know that custom bores can have different diameters than standard production bores, and that this can heavily influence velocity outcomes.

In reality, the 260 gives at least 50FPS more velocity than the 6.5CM for a given bullet, given identical conditions. On first glance, this may not seem like any real difference, but when handloading, one can load the 260 to lower pressures than the 6.5CM and still get identical performance, and this can have big benefits in bore longevity.

Now some might suggest that this makes the 6.5CM the more efficient cartridge. In my book that simply means that 'the more efficient cartridge' needs to be hot rodded in order to match the 'comparable' cartridge's performance; and that's never good news for fans of bore longevity.

So the deck is stacked in the Hornady manual in favor of the 6.5CM which was developed in-house at Hornady. An experienced reloader will recognize this after just a few minutes worth of paging back and forth in the book. That's what I did when I was looking for an actually good reason to adopt the 6.5CM anyway. But it just didn't stand up, not even on paper.

Compare this with Remingtons's proven track record of abandoning its own chamberings to lingering death in the marketplace.

Now don't get me wrong, they are both excellent choices; and for the newer 6.5 shooter, the 6.5CM makes a lot of sense. But it makes little sense to switch from the 260 to the 6.5CM. The 260 is just the superior cartridge. It would be just like giving the family cow away for some magic beans.

Years of shooting F Open has demonstrated to all that the 260 leaves some gold on the table to the 6.5-284. But the 6.5-284 is a barrel burner where the 260 gives far more reasonable bore life. I'm still shooting the custom 260 barrel that I first installed in around 2003-2004, and it's got several full seasons of 1000yd F open competition at Bodines in it. A 6.5-284 would have probably required replacement before getting half way through the second season.

Yes, the 260 might benefit from some small case capacity increase. But it would not benefit from any capacity decrease, which is precisely what the 6.5CM offers.

Accuracy wise, the edge goes to the better ammunition maker, not to either one of the chamberings.

As for magazine length arguments, this was already covered in my prior posting. Likewise for any scarcity of excellent 260 factory match offerings.

Don't take any of this on my word. Read the book.

Choose whichever chambering makes the best sense to you, but get the basic facts right, too.

Greg

PS Cody, this is not some personal issue between you and me. I just happen to have over15 years of experience with the 260 and think that it's currently undergoing same artificial stress as part of a marketing strategy in favor of the 6.5CM; and so I felt that we all just needed to get our facts straight if we wanted to make the comparison in real terms.
 
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I find my gas gun is a little harder on brass and I don’t get as many reloads out of it as I do in my bolt gun. I went with the cm just because I can always find brass or loaded rounds. It’s cheaper and I’m not good enough to shoot the difference. Where I live I don’t find .260 match as often.
 
Plenty of room in a magazine for .260 rounds. Factory or hand loads.

This statement is based on what bullet? Definitely not the case with say Bergers thst your trying to get close to the lands unless your shooting a 260 with a shorter freebore... I shot 260 for years, it was great, very accurate but mag limitations are what pushed me to 6.5cm, then 6.5x47L for brass life.

Sure you can say stuff 139L or 130 ELD, etc into a case but that isn't a solution for not being able to get Berger Hybrids close to the lands and stay within magazine length.

You can make 6.5cm brass out of 243, 260 and 308 brass as well. Hornady 6.5cm brass is cheap and shoots great. I am shooting 500pcs of LC 7.62 brass I converted right now in my 6.5cm semi.

I cant think of any reason why I would go with 260 over 6.5cm in a semi. Your gonna see pressure in the gasser before you fill that 260 case up and hot rod it.

Gasser vs bolt gun are 2 different animals.
 
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Plenty of room in a magazine for .260 rounds. Factory or hand loads.

Sounds like a ML disciple.

Anything the 260 can do in a gasser, the 6.5 creed can do as well. The 6.5 creed has the added benefit of being able to fit a wider variety of projectiles and have a plethora of reasonably priced off the shelf ammo. If you already have a 260 gasser, there’s nothing wrong with it, but if buying new, there’s no reason to get a 260 over a 6.5 creedmoor.

My vote: 6.5 creedmoor